Soap bar

ABSTRACT

hain fatty acid.

United States Patent Inventors James Francis Davies 5 R f c Cited Bmmbmulh; UNITED STATES PATENTS 3121: 13 Chem Ellesmere both of A 3,043,778 7/l962 Kelly 252/107 Appl. No 721,610 3,085,066 3/1963 Mitoray et al. 252/107 Filed Apt 16, 1968 3,284,362 ll/l966 Zussman 252/107 Patented Dec. 7, 1971 Primary Examiner Leon D. Rosdol Assignee Lever Brothers Company Assistant Examiner-P. E. Willis New York, N.Y. Altorney- Louis F. Kline, Jr. Priority Apr. 27, 1967 Great Britain 19,548/67 ABSTRACT: The discoloration of certain antibacterial comr r r pounds, halogenated o hydroxvdiphenyl ethers of the general formula V V" V (1)11 SOAP BAR T 3 Claims, No Drawings u.s. Cl 252/107, I 1 r 252/106 424/340 lh l li ,@lQEEQShPEiFE; X @1 5 ar H or s alo n and Int. Cl Clld 3/48 p jg a whole number from 1 to 5, in a soap bar is reduced by Field of Search including in the soap bar from 1 to 15% of free CH2 straight- 107; 424/172, 340 chain fatty acid.

SOAP BAR This invention relates to antibacterial soap bars.

Amongst the many classes of antibacterial compoundsthat have been recommended for use in toilet soap bars are a number of classes of halogenated phenols. Unfortunately many such phenolic compounds when incorporated into soap bars cause the bars to discolor when they are exposed to sunlight. Discoloration occurs even though usual preservatives such as chelating agents, 'e.g., ethylenediamine tetraacetic acid and free-radical inhibitors are incorporated in the bar.

I-Ialogenated phenols that have this disadvantage include halogenated o-hydroxydiphenyl ethers of the general formula:

in which, independently, X and X:, are halogen, X and X are hydrogen or halogen and p is a whole number from I to 5. Preferred halogens are bromine and chlorine, in particular chlorine.

It has now been discovered that when compounds of the above general formula are included in bars together with at least 1 percent of free fatty acid color deterioration in the bar is surprisingly reduced. The upper limit on the amount of fatty acid is about 15 percent, where the physical properties of the soap bar begin to be unduly affected.

Preferably X should be halogen and preferable should be ortho to the ether group (p=2 in this case).

A mixture of antibacterial compounds can be used, e.g., a mixture of compounds within the general formula or a mixture with other antibacterial compounds.

The amount of antibacterial compound of the above general formula can be between 0.1 and 5 percent by weight of the bar, preferably between 0.1 and 2 percent. The total amount of antibacterial compound or compounds in the bar will normally be between 0.5 and 5 percent, preferably 0.5 to 2 percent, by weight of the bar.

The invention therefore provides an antibacterial soap bar containing an antibacterial compound of the class herein defined and from I to 15 percent by weight of free fatty acid. The bar should preferably contain between 2 and I percent by weight of free fatty acid.

The free fatty acid should be a C -C substantially straightchain fatty acid and can advantageously be such an acid as stearic acid or myristic acid or mixtures of acids derived from coconut oil, tallow fat or palm kernel oil. Such fatty acid is a usual superfatting agent.

The antibacterial compound or compounds and the free fatty acid may be incorporated in any convenient manner either independently or together. The fatty acid can be released in the bar or soap from which the bar is made, for instance by the use of phosphoric acid as described in Netherlands application No. 6,709,575.

The invention is particularly applicable to 4,2',4-trichloro- 2-hydroxydiphenylether where, in the general formula, X,, X and X, are chlorine, X is hydrogen, p is 2 and X is ortho. EXPERIMENT l Soap mushes containing I percent, by weight of soap base, of 4,2',4'-trichloro-2-hydroxydiphenyl ether were prepared in beakers. The soap mush was formed from 10 g. of a soap base and 50 g. of water. The soap base was prepared from an 80/15/5 tallow/coconut/sperm oil distillate fat charge. Into separate mushes were incorporated, by weight of soap base, 0.5 percent of benzoic acid, 2 percent of palm kernel acid, percent of palm kernel acid and percent of palm kernel acid. The beakers were exposed to direct sunlight and the time taken for discoloration of the soap mushes to occur was noted. Benzoic acid was used since it is disclosed as a stabilizer for such compounds in US. Pat. No. 3,284,362. The following results were obtained:

Additive in soap in soap Time to discoloration of Soap bars were made from the soap base used in experiment 1 containing 1 percent by weight of 4,2',4-trichloro-2- hydroxydiphenyl ether. Into one set of soap bars was incorporated 2 percent by weight of palm kernel acid and into another bar 5 percent by weight of palm kernel acid. The time taken for discoloration of the soap bars to occur was measured when the bars were exposed to direct sunlight. The following results were obtained:

Time to discoloration of soap bar-weeks Additive in soap bar Z; in soap bar I l day Palm kernel acid 2 3 Palm kernel acid 5 3+ EXPERIMENT 3 Soap bars were prepared according to experiment 2 but instead of 4,2,4'-trichloro-2-hydroxydiphenylether the bars contained 3,5,6,3',5',6'-hexachloro-2,2'-dihydroxydiphenyl methane and a mixture of 3,5,4"tribromosalicylanilide (60percent) and 5,4'-dibromosalicylanilide (40percent). It was found that bars containing these antibacterial compounds were not stabilized against discoloration by incorporation of fatty acid in the bar.

EXPERIMENT 4 Soap bars were prepared according to experiment 2 but instead of 4,2,4'-trichloro-Z-hydroxydiphenylether the bars contained 4,4'-dichloro-2-hydroxydiphenylether. Similar results were obtained.

EXPERIMENT 5 Five sets of soap bars were prepared. All contained 1 percent of 4,2',4'-trichloro-2-hydroxydiphenylether. The five sets contained, respectively, 0.1 percent benzoic acid, 1 percent benzoic acid, 2.8 percent benzoic acid, 5 percent benzoic acid and 5 percent palm kernel acid, 2.8 percent benzoic acid is, on a molar basis, equivalent to 5 percent palm kernel acid.

After exposure to daylight the following results were obtained:

It was also found that the physical properties of the bar, softness, etc., were poorer with the bars containing more than 2 percent by weight of benzoic acid than with the other bars. EXPERIMENT 6 Soap bars were prepared containing 0.l, 0.2, 0.3 and 0.5 percent of 4,2',4-trichloro-2-hydroxydiphenylether, respectively, and various amounts of fatty acid superfat. Although some stabilization of color occurs at lower levels and ratios of superfat, it was found that preferably there should be at least 1 percent of superfat present in the bar and the weight ratio of superfat to antibacterial compound should be greater than 4:l.

What is claimed is:

1. An antibacterial toilet soap bar consisting essentially of, by weight, between 0.1 and 5 percent of an antibacterial compound of the general fo rmula *arirntu 

2. An antibacterial soap bar as claimed in claim 1, in which the antibacterial compound is 4,2'',4''-trichloro-2-hydroxydiphenylether.
 3. An antibacterial soap bar as claimed in claim 1, in which the antibacterial compound is 4,4-dichloro-2-hydroxydiphenylether. 